// Copyright 2015-2020 Parity Technologies (UK) Ltd.
// This file is part of OpenEthereum.

// OpenEthereum is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// OpenEthereum is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with OpenEthereum.  If not, see <http://www.gnu.org/licenses/>.

//! View onto block rlp.

use crate::BlockNumber;

use super::ViewRlp;
use crate::{
    bytes::Bytes,
    hash::keccak,
    header::Header,
    transaction::{LocalizedTransaction, TypedTransaction, UnverifiedTransaction},
    views::{HeaderView, TypedTransactionView},
};

use ethereum_types::H256;

/// View onto block rlp.
pub struct BlockView<'a> {
    rlp: ViewRlp<'a>,
}

impl<'a> BlockView<'a> {
    /// Creates new view onto block from rlp.
    /// Use the `view!` macro to create this view in order to capture debugging info.
    ///
    /// # Example
    ///
    /// ```
    /// #[macro_use]
    /// extern crate common_types as types;
    ///
    /// use types::views::{BlockView};
    ///
    /// fn main() {
    /// let bytes : &[u8] = &[];
    /// let block_view = view!(BlockView, bytes);
    /// }
    /// ```
    pub fn new(rlp: ViewRlp<'a>) -> BlockView<'a> {
        BlockView { rlp: rlp }
    }

    /// Block header hash.
    pub fn hash(&self) -> H256 {
        self.header_view().hash()
    }

    /// Return reference to underlaying rlp.
    pub fn rlp(&self) -> &ViewRlp<'a> {
        &self.rlp
    }

    /// Create new Header object from header rlp.
    pub fn header(&self, eip1559_transition: BlockNumber) -> Header {
        Header::decode_rlp(&self.rlp.at(0).rlp, eip1559_transition).unwrap_or_else(|e| {
            panic!(
                "block header, view rlp is trusted and should be valid: {:?}",
                e
            )
        })
    }

    /// Return header rlp.
    pub fn header_rlp(&self) -> ViewRlp<'a> {
        self.rlp.at(0)
    }

    /// Create new header view obto block head rlp.
    pub fn header_view(&self) -> HeaderView<'a> {
        HeaderView::new(self.header_rlp())
    }

    /// Return List of transactions in given block.
    pub fn transactions(&self) -> Vec<UnverifiedTransaction> {
        TypedTransaction::decode_rlp_list(&self.rlp.at(1).rlp).unwrap_or_else(|e| {
            panic!(
                "block transactions, view rlp is trusted and should be valid: {:?}",
                e
            )
        })
    }

    /// Return List of transactions with additional localization info.
    pub fn localized_transactions(&self) -> Vec<LocalizedTransaction> {
        let header = self.header_view();
        let block_hash = header.hash();
        let block_number = header.number();
        self.transactions()
            .into_iter()
            .enumerate()
            .map(|(i, t)| LocalizedTransaction {
                signed: t,
                block_hash: block_hash.clone(),
                block_number: block_number,
                transaction_index: i,
                cached_sender: None,
            })
            .collect()
    }

    /// Return the raw rlp for the transactions in the given block.
    pub fn transactions_rlp(&self) -> ViewRlp<'a> {
        self.rlp.at(1)
    }

    /// Return number of transactions in given block, without deserializing them.
    pub fn transactions_count(&self) -> usize {
        self.transactions_rlp().iter().count()
    }

    /// Return List of transactions in given block.
    pub fn transaction_views(&self) -> Vec<TypedTransactionView<'a>> {
        self.transactions_rlp()
            .iter()
            .map(TypedTransactionView::new)
            .collect()
    }

    /// Return transaction hashes.
    pub fn transaction_hashes(&self) -> Vec<H256> {
        self.transactions_rlp()
            .iter()
            .map(TypedTransactionView::new)
            .map(|t| t.hash())
            .collect()
    }

    /// Returns transaction at given index without deserializing unnecessary data.
    pub fn transaction_at(&self, index: usize) -> Option<UnverifiedTransaction> {
        self.transactions_rlp().iter().nth(index).map(|rlp| {
            TypedTransaction::decode_rlp(&rlp.rlp).unwrap_or_else(|e| {
                panic!(
                    "block transaction_at, view rlp is trusted and should be valid.{:?}",
                    e
                )
            })
        })
    }

    /// Returns localized transaction at given index.
    pub fn localized_transaction_at(&self, index: usize) -> Option<LocalizedTransaction> {
        let header = self.header_view();
        let block_hash = header.hash();
        let block_number = header.number();
        self.transaction_at(index).map(|t| LocalizedTransaction {
            signed: t,
            block_hash: block_hash,
            block_number: block_number,
            transaction_index: index,
            cached_sender: None,
        })
    }

    /// Returns raw rlp for the uncles in the given block
    pub fn uncles_rlp(&self) -> ViewRlp<'a> {
        self.rlp.at(2)
    }

    /// Return list of uncles of given block.
    pub fn uncles(&self, eip1559_transition: BlockNumber) -> Vec<Header> {
        Header::decode_rlp_list(&self.rlp.at(2).rlp, eip1559_transition).unwrap_or_else(|e| {
            panic!(
                "block uncles, view rlp is trusted and should be valid: {:?}",
                e
            )
        })
    }

    /// Return number of uncles in given block, without deserializing them.
    pub fn uncles_count(&self) -> usize {
        self.uncles_rlp().iter().count()
    }

    /// Return List of transactions in given block.
    pub fn uncle_views(&self) -> Vec<HeaderView<'a>> {
        self.uncles_rlp().iter().map(HeaderView::new).collect()
    }

    /// Return list of uncle hashes of given block.
    pub fn uncle_hashes(&self) -> Vec<H256> {
        self.uncles_rlp()
            .iter()
            .map(|rlp| keccak(rlp.as_raw()))
            .collect()
    }

    /// Return nth uncle.
    pub fn uncle_at(&self, index: usize, eip1559_transition: BlockNumber) -> Option<Header> {
        self.uncles_rlp().iter().nth(index).map(|rlp| {
            Header::decode_rlp(&rlp.rlp, eip1559_transition).unwrap_or_else(|e| {
                panic!(
                    "block uncle_at, view rlp is trusted and should be valid.{:?}",
                    e
                )
            })
        })
    }

    /// Return nth uncle rlp.
    pub fn uncle_rlp_at(&self, index: usize) -> Option<Bytes> {
        self.uncles_rlp()
            .iter()
            .nth(index)
            .map(|rlp| rlp.as_raw().to_vec())
    }
}

#[cfg(test)]
mod tests {
    use super::BlockView;
    use ethereum_types::H256;
    use rustc_hex::FromHex;
    use std::str::FromStr;

    #[test]
    fn test_block_view() {
        // that's rlp of block created with ethash engine.
        let rlp = "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".from_hex().unwrap();

        let view = view!(BlockView, &rlp);
        assert_eq!(
            view.hash(),
            H256::from_str("2c9747e804293bd3f1a986484343f23bc88fd5be75dfe9d5c2860aff61e6f259")
                .unwrap()
        );
        assert_eq!(view.transactions_count(), 1);
        assert_eq!(view.uncles_count(), 0);
    }
}
